input transformer - mumetal casing etc.

Alexontherocks · 19th December 2011, 02:09 PM

Dear All, investingating the possibility of building a pmillet universal PP amplifier

Push-pull KT88 class A amp with "universal" driver PCB

I researched one of the most expensive components (on the PCB that is)...the input transformer.

either a sowter or lundhal will do according to pete millet. Here is the link to the sowter product

3575

To reduce cost and shipping problems I would have liked to have all the transformer parts made and shipped through edcor electronics. I have contacted them in relation to the sowter part (to have it "cloned") and the reply is the following:

1. They don't use mumetal cans or electrostatic shielding
2. "What we can do is the 1:1 ratio PC and PCW series transformers (on our website) and could put a external copper shield on the transformer for an additional cost"

I am no engineer and would like to ask some input to some of the guys on the forum. Can such a solution work? Waht would be a good choice among the EDCOR products to emulate the charaacteristics of the sowter part?

Thanks
Alex

Alexontherocks · 19th December 2011, 02:16 PM

one of the solutions might be this:

EDCOR Electronics Corporation. PCW10K/10K

or

EDCOR Electronics Corporation. WSM10K/10K

comments?

Thanks again
Alex

male42 · 19th December 2011, 02:24 PM

If I understand you correctly, then the input transformer should have a screen. preferably of magnetic material. such as permalloy, nickel-containing alloys. sometimes requires a dual screen. copper in this case is not suitable.

Alexontherocks · 19th December 2011, 02:26 PM

The sowter seems to have one, I guess the edcor should have one as well...

what would be the effect from using copper instead of a megnetic material?

pieter t · 19th December 2011, 02:31 PM

[QUOTE=Alexontherocks;2826761
what would be the effect from using copper instead of a megnetic material?[/QUOTE]

No screening from low frequency stray fields.

male42 · 19th December 2011, 02:32 PM

you need to protect the transformer coil from external parasitic interference with magnetic origin. such as power transformer. Copper does not have this property

Alexontherocks · 19th December 2011, 02:35 PM

Is there anyway to obtain sheets of magnetic material and have them formed to create a screen?

In conclusion you all foresee problems with using the EDCOR alternative, correct?

I have plenty of tools and machines (a friend has a CNC/metalwork shop) so forming, bending and such would not be a problem...

SY · 19th December 2011, 02:36 PM

Go Cinemag. Prices are very reasonable and the quality is as good/better than Sowter. The input transformer I've been using seems identical in performance to the Jensen JT11P1 at half the price.

Alexontherocks · 19th December 2011, 02:38 PM

cinemag's site seems to be down...

SY · 19th December 2011, 02:42 PM

Audio Transformers By Cinemag Inc.

Came right up for me.

19th December 2011, 02:09 PM	#1
Alexontherocks Account disabled at member's request Join Date: Jul 2009	input transformer - mumetal casing etc. Dear All, investingating the possibility of building a pmillet universal PP amplifier Push-pull KT88 class A amp with "universal" driver PCB I researched one of the most expensive components (on the PCB that is)...the input transformer. either a sowter or lundhal will do according to pete millet. Here is the link to the sowter product 3575 To reduce cost and shipping problems I would have liked to have all the transformer parts made and shipped through edcor electronics. I have contacted them in relation to the sowter part (to have it "cloned") and the reply is the following: 1. They don't use mumetal cans or electrostatic shielding 2. "What we can do is the 1:1 ratio PC and PCW series transformers (on our website) and could put a external copper shield on the transformer for an additional cost" I am no engineer and would like to ask some input to some of the guys on the forum. Can such a solution work? Waht would be a good choice among the EDCOR products to emulate the charaacteristics of the sowter part? Thanks Alex

19th December 2011, 02:24 PM	#3
male42 diyAudio Member Join Date: Jun 2010 Location: Kemerovo Russia	If I understand you correctly, then the input transformer should have a screen. preferably of magnetic material. such as permalloy, nickel-containing alloys. sometimes requires a dual screen. copper in this case is not suitable. __________________ __________________http://www.mostsound.narod.ru

19th December 2011, 02:32 PM	#6
male42 diyAudio Member Join Date: Jun 2010 Location: Kemerovo Russia	you need to protect the transformer coil from external parasitic interference with magnetic origin. such as power transformer. Copper does not have this property __________________ __________________http://www.mostsound.narod.ru

19th December 2011, 02:36 PM	#8
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	Go Cinemag. Prices are very reasonable and the quality is as good/better than Sowter. The input transformer I've been using seems identical in performance to the Jensen JT11P1 at half the price. __________________ If there's a sucker born every minute, where do the rest of them come from?

19th December 2011, 02:42 PM	#10
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	Audio Transformers By Cinemag Inc. Came right up for me. __________________ If there's a sucker born every minute, where do the rest of them come from?


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19th December 2011, 02:16 PM	#2
Alexontherocks Account disabled at member's request Join Date: Jul 2009	one of the solutions might be this: EDCOR Electronics Corporation. PCW10K/10K or EDCOR Electronics Corporation. WSM10K/10K comments? Thanks again Alex

19th December 2011, 02:26 PM	#4
Alexontherocks Account disabled at member's request Join Date: Jul 2009	The sowter seems to have one, I guess the edcor should have one as well... what would be the effect from using copper instead of a megnetic material?

19th December 2011, 02:31 PM	#5
pieter t Account disabled at member's request Join Date: Apr 2009	[QUOTE=Alexontherocks;2826761 what would be the effect from using copper instead of a megnetic material?[/QUOTE] No screening from low frequency stray fields.

19th December 2011, 02:35 PM	#7
Alexontherocks Account disabled at member's request Join Date: Jul 2009	Is there anyway to obtain sheets of magnetic material and have them formed to create a screen? In conclusion you all foresee problems with using the EDCOR alternative, correct? I have plenty of tools and machines (a friend has a CNC/metalwork shop) so forming, bending and such would not be a problem...

19th December 2011, 02:38 PM	#9
Alexontherocks Account disabled at member's request Join Date: Jul 2009	cinemag's site seems to be down...

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